The present invention relates to the field of orthotic devices. More specifically, the present invention relates to a self-adjustable, or easily modified functional orthotic device and method of using the orthotic device.
Orthotic inserts have been used for many years in an effort to correct the alignment and functional pathology of the human foot. U.S. Pat. No. 454,342 shows one of the earliest orthotic inserts used for the supportive, static, correction of a flat foot deformity. Such an insert is generally known as an xe2x80x9carch support.xe2x80x9d
More recent orthotic inserts allow for the variable placement of static components. For example, in U.S. Pat. No. 4,800,657, the insert provides adjustment plugs to xe2x80x9cfine tunexe2x80x9d the supportive contour of the insert. Another recent example is U.S. Pat. No. 4,841,648 which shows a supportive insole that can be modified by the user. The insole consists of different attachable insole pieces which vary in size, shape and density.
Although modern insert design, which is generally supportive in structure, can be indirectly effective in treating lower extremity functional pathology, they also can and often do fail to achieve a noticeable functional improvement. Ideally, a foot orthosis should be functional, supportive and comfortable. A foot orthosis should also be self-adjustable or easily modified to account for the variable lower extremity mechanical factors. The orthosis should treat the leg, ankle and foot as a system complex functioning through the total gait cycle. The foot orthosis should not be limited to the treatment of positional static biomechanical microcosms of the lower extremities. For example, static orthotic inserts, having a depression or a support, are commonly used to accommodate a callus. A callus however, should usually be treated dynamically because a callus is predominantly a functional foot problem. Unfortunately, the knowledge currently available does not include a direct treatment method to accomplish the results that the instant invention provides.
Sophisticated clinical examination techniques and, in some cases, computer monitored xe2x80x9cpressure dataxe2x80x9d studies are used to establish a biomechanical basis and to confirm the effectiveness of the prescribed treatment using shoe inserts. Yet, in many instances, the supportive orthotic treatment prescribed does not correct the patient""s foot disorder. It is not unusual for a foot specialist to make an illogical, if not questionable adjustment to an insert, based upon current treatment options and knowledge, and find that the adjustment corrected the symptomatic condition. This is because treatment knowledge has overlooked direct functional application of the orthosis, which is sometimes serendipitously achieved.
Because most patients can actually feel the normal neurological responses of the foot and lower extremities, they can often know when their body is more or less working properly as a result of their symptomatic conditions. Moreover, even when there is initial discomfort caused by an orthosis, the patient can often correctly predict future tolerance of the orthosis and improvement of the symptomatic condition. Although the foot specialist uses objective factors to correct foot disorders, he or she also uses subjective factors in evaluating the patients comfort with the prescribed orthosis. Therefore, the patient""s subjective perspective can often be as important to correct treatment as the foot specialist""s objective perspective.
Ideally, the objective of orthopedic foot treatment is to improve functional alignment and symptomology of the foot and lower extremities through as much of the gait cycle as possible. Generally speaking, even regarding mild foot pathology, an appropriate surgery is more likely to achieve the long-term goal of treatment in comparison with the use of a contemporary foot orthosis. The reason for the higher success rate of surgery is at least in part, because surgery can provide a more permanent functional alignment and symptomatic improvement. In addition, the combination of wear changing characteristics of a shoe and a conventional supportive orthotic insert which flattens with use, can be unpredictable. Another reason is because there is no conveniently effective positive adjustment mechanism for the inevitable deteriorating change of the shoe or insert.
Because of the expense, discomfort and potential risks associated with surgery, orthotic treatment devices are widely used to improve symptomatic conditions of the foot and lower extremities. Even with our most advanced analytical techniques however, we have only a basic idea of how each individual biomechanical system works as an efficient unit. This is especially true with respect to the foot and lower extremities. We know that we can alter the walking surface by using a shoe insert. The change in a walking surface creates a biomechanical system reaction extending from the foot proximally to the axial skeleton. In time, changing the position of the foot""s anatomical alignment by supporting it with an insert can modify system function with the possibility of influencing the biomechanical activity through the total gait cycle. Nevertheless, current insert adjustments, even when effective, almost universally are considered by patients and doctors to be inconvenient, time consuming and costly. The result can be that the patient who needs to be treated will avoid seeing a foot specialist for as long as possible. This delay can cause the condition of the patient to deteriorate further.
What is needed is a shoe insert design and method of treatment that will allow the wearer to experience direct and immediate functional benefit and to make simple adjustments for improved function. Improved function should result in improved anatomical alignment. The patient should be able to take an active responsibility in the empirical treatment of themselves, with respect to varying circumstances. The device should allow a dynamic interaction between the wearer, the shoe and the insert to place the patient in more effective control of his or her treatment plan. Further, the orthosis should be adaptable to many types of conventional foot orthoses to enhance their capability to improve function and comfort to the wearer.
This invention relates to a new dynamic, removable, mechanical foot orthosis and shoe insole leverage system that is comprised of a plate overlaying a fulcrum upon which the plate functionally xe2x80x9csee saws.xe2x80x9d The foot leverage system can be used together with conventional shoes by inserting the fulcrum and foot plate within the conventional shoe. The foot leverage system is a functional mechanism that can move the foot from one position to another without direct assistance from extrinsic or intrinsic muscle activity. Instead, it utilizes the naturally occurring displacement of the center of body pressure to create torque variations around the fulcrum which creates a resultant rotation of the plate and the foot about the fulcrum.
The rate of rotation of the inventive plate about the fulcrum can be changed by:
1. changing the rigidity of the plate;
2. adding or removing variable density materials or compressible spring-like materials on either side of the fulcrum;
3. modifying the modulus of elasticity of a hinge type fulcrum member that is positioned between the plate and the inner sole; or
4. modifying the dimensions, position and design of the inventive fulcrum.
The initiation of rotation in the stance phase as well as the direction or angle of movement of the foot-supporting plate, relative to the shoe, can be altered by changing the shape of the fulcrum in height, width, radius of curvature, length or position beneath the inventive plate.
In a preferred embodiment of the present invention, a uniform fulcrum is removably attached to the shoe sole or to the plate. The plate is positioned on the top of the fulcrum and typically extends from the heel to the forefoot area. In another preferred embodiment, the fulcrum has an I-shaped cross section and has resilient, flexible material at the relatively narrow center section. In another preferred embodiment, the fulcrum varies in width, height and radius of curvature along its length. Another preferred embodiment includes resilient material, of desirable density, between the shoe sole and the inventive plate, in front and back of the inventive fulcrum. The resilient material is generally less dense than the density of the fulcrum material. The resilient material in front of the fulcrum is nearly always less dense than the density of the fulcrum to allow for the forward rotation of the plate and the wearer""s foot. The density of the resilient material in front of the fulcrum can also be different than the density of the resilient material behind the fulcrum to allow for a different rate of rotation to the rear than to the front of the fulcrum.
In another preferred embodiment, the fulcrum is formed with a step-shaped ledge either on the inventive plate or integral with a shoe sole insert. Resilient material of desirable density, generally less than density of the fulcrum, may be positioned in the gap between the inventive plate and the top of the inner shoe sole or welt. The fulcrum member may also be configured to include multiple segmented units to create a rotatable fulcrum axis.
In another preferred embodiment, the inventive plate is molded to the identical or approximate shape of the user""s foot.
The invention also describes a method for changing the force curve manifestation of the foot. The force curve, which is an indicator of function, can be changed by adjusting the inventive plate and fulcrum to arrest the abnormal force-related symptomatic conditions of the foot. An object of the present invention is to create a significant functional displacement of the force curve, either medially or laterally, from a pathologic path of progression to one that is more biomechanically and symptomatically desirable. As will be explained in more detail herein, this is achieved by creating torque variations around an artificial functional axis with the facility of simple positional reorientation. The positional reorientation is capable of directly or indirectly affecting the function of all of the periods of the gait cycle.
The invention also describes a method for treating different foot pathologies including: pes planus (excessively pronated low arched foot), pes cavus (excessively supinated high arched foot) and achilles tendonitis. By treating pes planus, the inventive method can prevent, reduce or eliminate many of the pathologic excessive pronatory sequelae such as: bunions, neuromas, hammertoes, hallux limitus, forefoot supinatus, plantar calluses, plantar fasciitis, cuboid syndrome, heel spur syndrome, tibialis posterior tendonitis, shin splints, medial knee retinaculitis and chondromalacia patella. By treating pes cavus, the inventive method can increase the stability of the lower extremities and improve the positional relationships of the foot structure to the leg. By treating achilles tendonitis, the inventive method can reduce stress and decrease or eliminate inflammation of the achilles tendon.
The invention also describes a mapping feature that directs the treating practitioner or the wearer to adjust the orthosis according to the symptomatic condition of the foot.
Another object of the present invention is to align more properly the foot and lower extremities which results from more efficient movement throughout the entire gait cycle. During the contact period, a plate in combination with a fulcrum of variable width and height supports the calcaneus posteriorly. During the midstance period, force displacement in the foot creates a shift of torque across the fulcrum which causes a rotation of the plate and produce appropriate associated motion and positional change in the foot and leg. During the propulsive period, the alignment and function of the foot and leg are improved relative to prior orthotic treatment systems and this alignment can carry into the swing phase.
Another object of the invention is to create a significant displacement of the force curve, either medially or laterally, from a pathological path of progression to one that is associated with less symptomology and that is more desirable. This is achieved with the present invention by creating torque variations about an artificial functional axis with the facility of simple positional reorientation of the fulcrum. The torque variations are capable of directly or indirectly affecting all periods of the gait cycle. An interplay of ground reactive force, plate reactive force and center of body pressure results in motion around the axis of the fulcrum. Sagittal, transverse and frontal plane motions of the inventive plate are directly influenced by fulcrum axis placement and shape which results in the simultaneous pronation or supination of the supported foot to variable degrees and within the variable time frame of the total gait cycle.
The present invention offers advantages over existing orthotic devices in that the instant orthotic device can:
1. directly generate mechanical foot function, primarily during midstance, which can be corrective and beneficial;
2. directly or indirectly affect the function of all periods of the gait cycle;
3. accommodate the wearer""s needs as circumstances change by performing a simple adjustment;
4. be used to facilitate an existing shoe insert;
5. be worn by itself; and
6. be adjusted to fit with different shoe types that would otherwise not accept a standard type of insert.
The present invention changes the midstance function and position of the foot. The midstance period, during walking is the only complete time frame segment that a single foot supports the entire body weight. As such, midstance foot function has a significant impact upon the remainder of the gait cycle lower extremity function. By changing the midstance function and position of the foot, the rest of the gait cycle, including the swing cycle, can be indirectly effected.
Another advantage of the present invention is its facility to assist the venous pump mechanism of the lower extremity. Ankle swelling and related circulatory conditions associated with venous stasis can be improved by the repetitive movement of the inventive orthotic device and the associated change of foot function.
Another advantage of the present inventive orthotic system is that the orthotic can be adjusted by the wearer to modify the shoe wear pattern. The resulting adjustment can reestablish foot balance in the worn shoe and redirect foot mechanics for more evenly worn shoes to enhance the shoe life and improve comfort.
Another advantage of the present inventive orthotic system is that the orthotic can be adjusted by the wearer to accommodate different physical or sport activities that are dependant upon efficient and specific lower extremity biomechanical function. For example, a golfer""s swing may be improved by modifying the golfer""s push-off shoe insert to provide better foot propulsion and an improved drive swing. The same individual may have a different propulsive requirement during a running activity and a simple adjustment to the fulcrum position can provide the desired change in function.
Pedobarographs are provided which illustrate the dramatic change in center of pressure curves (force curves) when the inventive device is used by a patient who has objective findings of excessive pronation. When using the inventive device, the center of pressure curves change from an undesirable pronated walking center of pressure distribution to a more desirable, and more normal walking center of pressure distribution.